Thermostatic switch



July 9, 1929. J, RAY

THERMOSTATIC SWITCH Filed Dec. 1922 a? 6 #5" 66' 66 9 w w M \v Q W' I 4 W lq 4 1. 6 1 1 Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

EUGENE J. BAY, OF BEVERLY, MASSACHUSETTS, ASSIGNOR TO UNITED SHOE MA- CHINERY CORPORATION, OF PATERSON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

THERMOSTATIC SWITCH.

Application filed December 7, 1922. Serial No. 605,543.

The present invention relates to a thermostatic switch for making and breaking an electric circuit and is designed primarily for use in connection with thread waxing devices for applying wax to sewing thread, although it is equally capable of use in other relations.

The object of the invention is to provide a thermostatic switch of novel and improved construction and operation, and with this object in view the invention consists in the thermostatic switch hereinafter described and particularly defined in the claims.

In the drawing illustrating the preferred embodiment of the invention, Fig.1 is a side View, partly in section, of a th ead waxing device comprising a. thermostatic switch embodying the several features of the present invention; Fig. 2 is an enlarged plan-view of certain of the parts show/n in Fig. 1, and particularly of the switch; and Figs. 3' and 4 are views in plan and vertical section, respectively, illustrating an adjustment in the connections between the movable contact member of the switch and the heat responsive member.

The present invention is illustrated as. embodied in the thread waxing device forming the subject matter of an application filed of even date herewith as a continuation in part of an application filed July 27, 1920, Ser. No. 399,281.

The thread waxing device in connect-ion with which the present invention is illustrated comprises a wax receptacle 10 supported upon a support 12 to permit it to be raised and low- P ered with relation to the support.- The wax receptacle 10 is normally maintained in the position illustrated in Fig. 1, in which position the top of the receptacle .is closed by a cover plate 14. One portion 16 of the cover plate is hinged and permits, when raised, introduction of fresh lumps of wax into the receptacle. The mechanism for heating the wax within the receptacle comprises two'heating coils, each received within a hollow column 18, the top of which is shown in Fig. 2.

The thread enters the wax receptacle through an opening 20 in the cover plate and passes downwardly through a thread guide and thence upwardly through the cover and through a stripping device 22 by which the surplus wax is stripped from the thread.

The thermostatic switch of the present invention is Shown as arranged to control the operation of one of the heating coils. The swltch comprises a heat responsive member 24 m the form of a coiled metal strip,received within a hollow column 26 depending from and secured to the under side of the cover plate as illustrated in Fig. 1. The lower end of the metal coil is secured to a bracket 28 by means of ascrew'29 passing through a vertical slot in the bracket, the arrangement being such as to hold the lower end of the coil from rotation while permitting a slight vertical movement as the coil expands or contracts. The upper end of the metal coil is secured by a set screw 32 to a vertical shaft 36 journaled in laterally exte ded portions 38, 40 of the bracket 28. The movable contact member of the improved thermostatic switch is indicated at 42 and together with the terminal connections for the heating coils is located Within an enclosure 44 formedby side walls 46 upstanding from the cover plate 14. The contact member 42 is a-flat U-shaped piece of metal and is provided with knife edges 48 at the ends of its arms Which are received in grooves 50 in the ends of corresponding arms of a U-shaped bracket 52 secured to and insulated from one of the side walls 'of the enclosure.' The contact member is thus pivotally mounted and constitutes a lever movable about its pivot to make and break the circuit of one of the heating coils',"as will be described. The contact member 42 is provided with contact points 54, 56 adapted to cooperate with contact oints 58, 60 on' the ends of adjusting screws 62, 64 in the opposed arms of a bracket 66 secured to and insulated from one of the side walls, as clearly shown in Fig. 2. 1 The rotations of the vertical shaft 36 under expansion and contraction of the heat responsive member 24 are transmitted to the movable switch member 42 by a coiled spring 68, one end of which is connected to the contact member 42 and the second end of which is connected to an i sulating pin 70 secured in theend of an arm 72' mounted upon the u per end of the vertical shaft 36. During the o eration of the thread waxing device, as t e vertical shaft 36 is rotated by the heat responsive member in accordance with variations in the temperature of the molten wax, the insulating pin70 is moved with the arm 72 and the coiled'spring 68 operates to cause the contact member 42 to snap against eitherof the contacts 58, 60, the contact 58 being of insulating material, according as the spring passes to either side of the pivotal point of the switch member. After the contact member 42 is moved a ainst either of the contacts 58, 60, itis held rmly against this contact until it is snap ed against the other contact.

W lienever the temperature of the wax in the wax receptacle falls below the predetermined point at which proffer impre ation of the thread occurs, the contact mem et 42 will have been moved into contact with the contact 60, in which position a circuit is completed from a source (not shown) through the lead wire 76, lead 78 down through one of the heating coils, thence upwardly through the lead 80 to a connecting post 82 electrically connected with the bracket 66, thence through the bracket to the contact 6.0, through the contact member 42, through the bracket 52 to the 'connectin post 84 in a shelf 86 projecting from the hr lead. 88 completing the circuit. The second heating coil is in parallel with the foregoing circuit, the connections leading directly to the connecting posts 83, 84. When the temperature of the wax has risen to a predetermined point, the arm 72 will have been rotated by the heat responsive member from the position illustrated in Fig. 3 to the position illustrated in Fig. 2, and during such rotation, the

spring 68 will pass beyond the knife edges 48 and its tension will operate to suddenly snap I the .contact member against the insulating contact 58. When. the contactmember leaves the contact 60, the heating coil includedin the first of the circuits above. referred .to, is out out of circuit and as the contact; member is held against the insulatnig contact 58 this condition continues to exist until the temperature of the wax has fallen to a point such that the return movement of the arm 72 under the contraction of. the heat responsive member 24, brings the spring 68 tothe right ofthe pivotal point of the contact member, and at such time the latter is immediately,

snapped to the right and again makes contact wit the contact to throw again the heating coil into circuit. 7

With this construction of the thermostatic switch it will be observed that there exists a considerable range of temperature within which the contact member remains stationary, corresponding to the interval between the movements of the arm 72 from a position 'in-which the contact member makescontact "in temperature of the wax. It will also be observed that the exact extent of this range through which the contact member remains stationary may adjusted by adjustment of acket 52, and thence through the the adjusting screws 62, 64. Thus, for example, the switch may be adjusted so that the parts will assume the position illustrated in Figs. 1 and 3, when a temperature of, say, 220 F. is reached, and so that the contact member will remain stationary against the contact 60 until the temperature of the wax has reached 240 F. At this time the position of the arm 72 will be such as to cause the contact member to snap-to the left and into contact with the contact 58. When the temperature drops, following the cutting out of the heating coil in t! 1e above outlined manner,

the contact member continues to remain in this same position .until the temperature has again fallen to 220 F.. when the arm '7 2 will have assumed a position such as to cause 94 is journaled. The worm engages a worm wheel 96, the latter being secured to the upper end of the shaft 36 by a pin or otherwise. The end of the worm shaft 98 is vprovided with a hole 100 for the reception of a tool by which the worm shaft and worm may be rotated. Upon rotation of the worm, the arm 72 is caused to rotate relatively to the shaft 36, thus affording a convenient man- .ner of adjustment of the temperature limits within which it is desired to maintain the wax. After the desired adjustment has been secured, further rotation of the shaft 36 under .the influence of the heat responsive member 24 is transmitted through the worm wheel 96 and worm 94 to the arm 72 exactly as if the connection between the shaft and the armwere rigid. i

It will be observed that when the maximum temperature limit is reached and one ofthe, heatin coils is cut out of circuit, no arcing takes place at the contact points. Furthermore, the construction of the switch itself is such that upon' attainment of either the maximum "or minimum temperature limits, the coiled spring 68 operates to sna the contact member with considerable orce, thus insuring quick and positive operation of the switch and a corresponding desirable quick make or break of the circuit.

While the'illustrated construction of thermostatic switch is particularly adapted for use in connection with thread waxing devices for applying wax to sewing thread, it will be understood that the invention may be embodied in forms other than that illustrated, andutilized for purposes other than those aboveset forth, within the scope of I the following claims.

The invention having been thus described, what is claimed is:

1. A thermostatic switchhaving, in combination, a switch member for making and upon movement of the spring by the arm past the pivot of the switch member and stops for limiting the movement of the switch member in each direction.

2. A thermostatic switch having, in combination, a switch member for making andbreaking an electric circuit, and thermostatic means for oscillating the same including a heat responsive member, a shaft connected thereto to be rotated thereby, an arm journaled upon the shaft, a worm journaled in thearm, a worm wheel engaging the worm secured to the shaft for aflording adjustment between thearm and shaft, a spring connecting the arm and switch member arranged to cause oscillation of the switch member upon movement of the spring by the arm past the pivot of the switch member, and stops for limiting the movement of the switch member in each direction.

3. A thermostaticswitch having, in combination, a contact point, a pivoted switch member and thermostatic means for oscillating the switch member including a heat responsive coil of metal, a shaft about which said coil is arranged and to which one end of the coil is connected, an arm upon the shaft,

a spring connecting the arm and switch mem ber arranged-to snap the latter into and out of engagement with the contact point accordingly as the arm is moved past the pivot of the switch member and a stop for limiting the movement of the switch member away from the contact oint.

4. A thermostatlc switch having, in combination, a contact point, a pivoted switch member and thermostatic means for oscillating the switch member including a heat responsive coil of metal, a shaft aboutwhich said coil is arranged and to which one end of the coil is connected, an arm adjustabl'y mounted upon the shaft, a spring connecting the arm and switch member arranged to snap the latter into and out of engagement with the contact point accordingly as-the arm is moved past the pivot of the'switch member.

5. A thermostatic switch having, incom bination, a contact point, a pivoted switch member and thermostatic means for oscillating the switch member including a heat responsive coil of metal, a shaft about which said coil is arranged and to which one end of the coil is connected, anarm journaled upon the shaft, a worm journaled in the arm, a

' worm wheel engaging the arm and secured to the shaft for affording adjustment between the arm and the shaft and a spring connecting the arm and switch member arranged to snap the latter into and out of engagement with the contact point accordingly as the arm is moved past the pivot of the switch member.

6. A thermostatic switch having, in combination, a contact point, a pivoted switch member and thermostatic means. for oscillat- .ing the switch member including a heat responsive coil of metal, a shaft about which said coil is arranged and to which one 'end of the coil is connected, an arm upon the shaft, a"

spring connecting the arm and switch member arranged to snap the latter into and out of engagement with the contact point-accordingly as the arm ismoved past the pivot of the switch member, means for adjusting the arm about the shaft to adjust the temperature member arranged to operate the switch memher only upon the attainment by the heat responsive member of maximum or minimum temperature limits, means for adjusting the maximum and minimum temperature limits, and means for adjusting the arm with relation tothe heat responsive member to adjust the temperature range.

' EUGENE J RAY. 

